7 Popular Unit Test Naming Conventions

The article presents a compiled list of unit tests naming strategy that one could follow for naming their unit tests. The article is intended to be a quick reference instead of going through multiple great pages such as following. That said, to know greater details, please feel free access one of these pages listed below and know for yourself.

Following are 7 popular unit tests naming conventions that are found to be used by majority of developers and compiled from above pages:

MethodName_StateUnderTest_ExpectedBehavior: There are arguments against this strategy that if method names change as part of code refactoring than test name like this should also change or it becomes difficult to comprehend at a later stage. Following are some of the example:

isAdult_AgeLessThan18_False

withdrawMoney_InvalidAccount_ExceptionThrown

admitStudent_MissingMandatoryFields_FailToAdmit

MethodName_ExpectedBehavior_StateUnderTest: Slightly tweeked from above, but a section of developers also recommend using this naming technique. This technique also has disadvantage that if method names get changed, it becomes difficult to comprehend at a later stage. Following is how tests in first example would read like if named using this technique:

isAdult_False_AgeLessThan18

withdrawMoney_ThrowsException_IfAccountIsInvalid

admitStudent_FailToAdmit_IfMandatoryFieldsAreMissing

test[Feature being tested]: This one makes it easy to read the test as the feature to be tested is written as part of test name. Although, there are arguments that the “test” prefix is redundant. However, some sections of developer love to use this technique. Following is how the above tests would read like if named using this technique:

testIsNotAnAdultIfAgeLessThan18

testFailToWithdrawMoneyIfAccountIsInvalid

testStudentIsNotAdmittedIfMandatoryFieldsAreMissing

Feature to be tested: Many suggests that it is better to simply write the feature to be tested because one is anyway using annotations to identify method as test methods. It is also recommended for the reason that it makes unit tests as alternate form of documentation and avoid code smells. Following is how tests in first example would read like if named using this technique:

IsNotAnAdultIfAgeLessThan18

FailToWithdrawMoneyIfAccountIsInvalid

StudentIsNotAdmittedIfMandatoryFieldsAreMissing

Should_ExpectedBehavior_When_StateUnderTest: This technique is also used by many as it makes it easy to read the tests. Following is how tests in first example would read like if named using this technique:

Should_ThrowException_When_AgeLessThan18

Should_FailToWithdrawMoney_ForInvalidAccount

Should_FailToAdmit_IfMandatoryFieldsAreMissing

When_StateUnderTest_Expect_ExpectedBehavior: Following is how tests in first example would read like if named using this technique:

When_AgeLessThan18_Expect_isAdultAsFalse

When_InvalidAccount_Expect_WithdrawMoneyToFail

When_MandatoryFieldsAreMissing_Expect_StudentAdmissionToFail

Given_Preconditions_When_StateUnderTest_Then_ExpectedBehavior: This approach is based on naming convention developed as part of Behavior-Driven Development (BDD). The idea is to break down the tests into three part such that one could come up with preconditions, state under test and expected behavior to be written in above format. Following is how tests in first example would read like if named using this technique:

My personal favorite is naming unit tests based on the writing features of the class under test. It helps me to make sure that a class follows single responsibility. It also aids a great deal in code refactoring.

Ajitesh has been recently working in the area of AI and machine learning. Currently, his research area includes Safe & Quality AI. In addition, he is also passionate about various different technologies including programming languages such as Java/JEE, Javascript and technologies such as Blockchain, mobile computing, cloud-native technologies, application security, cloud computing platforms, big data etc.

2 Comments

I am a fan of your seventh approach: Given_Preconditions_When_StateUnderTest_Then_ExpectedBehavior. I omit some underscores (GivenPreconditions_WhenStateUnderTest_ThenExpectedBehavior) but it’s the same idea.